Hyperspectral imaging system

Abstract

This invention relates to a hyperspectral imaging system for denoising and/or color unmixing multiple overlapping spectra in a low signal-to-noise regime with a fast analysis time. This system may carry out Hyper-Spectral Phasors (HySP) calculations to effectively analyze hyper-spectral time-lapse data. For example, this system may carry out Hyper-Spectral Phasors (HySP) calculations to effectively analyze five-dimensional (5D) hyper-spectral time-lapse data. Advantages of this imaging system may include: (a) fast computational speed, (b) the ease of phasor analysis, and (c) a denoising algorithm to obtain the minimally-acceptable signal-to-noise ratio (SNR). An unmixed color image of a target may be generated. These images may be used in diagnosis of a health condition, which may enhance a patient's clinical outcome and evolution of the patient's health.

We claim: 
     
       1. A hyperspectral imaging system for generating an unmixed color image of a target, comprising:
 an optics system; and 
 an image forming system; 
 wherein:
 the optics system comprises at least one optical component; 
 the at least one optical component comprises at least one optical detector; 
 the at least one optical detector has a configuration that:
 detects a target radiation, which is absorbed, transmitted, refracted, reflected, and/or emitted by at least one physical point on the target, wherein the target radiation comprises at least two target waves, each wave having an intensity and a different wavelength; 
 detects the intensity and the wavelength of each target wave; and 
 transmits the detected target radiation, and each target wave's detected intensity and wavelength to the image forming system; 
 
 the image forming system comprises a control system, a hardware processor, a memory, and a display; and 
 the image forming system has a configuration that:
 forms a target image of the target using the detected target radiation, wherein the target image comprises at least two pixels, and wherein each pixel corresponds to one physical point on the target; 
 forms at least one intensity spectrum for each pixel using the detected intensity and wavelength of each target wave; 
 transforms the formed intensity spectrum of each pixel by using a Fourier transform into a complex-valued function based on the intensity spectrum of each pixel, wherein each complex-valued function has at least one real component and at least one imaginary component; 
 forms one phasor point on a phasor plane for each pixel by plotting the real value against the imaginary value of each pixel; 
 maps back the phasor point to a corresponding target image pixel on the target image based on the phasor point's geometric position on the phasor plane; 
 generates or uses a reference color map; 
 assigns a color for each phasor point on the phasor plane by using the reference color map; 
 transfers the assigned color to the corresponding target image pixel; 
 generates a color image of the target based on the assigned color; and 
 displays the color image of the target on the image forming system's display. 
 
 
 
     
     
       2. The hyperspectral imaging system of  claim 1 , wherein the image forming system has a configuration that generates the reference color map by using phase modulation and/or phase amplitude of the phasor points. 
     
     
       3. The hyperspectral imaging system of  claim 1 , wherein the reference color map has a uniform color along at least one of its coordinate axes. 
     
     
       4. The hyperspectral imaging system of  claim 1 , wherein:
 the reference color map has a circular shape, which forms a circular reference color map; 
 the circular reference color map has an origin, and a radial direction, and an angular direction with respect to the origin of the circular reference color map; and 
 wherein the image forming system has a configuration that:
 varies color in the radial direction and keeps color uniform in the angular direction to form a radial reference color map; 
 varies color in the angular direction and keeps color uniform in the radial direction to form an angular color reference map; and/or 
 varies brightness in the radial direction and/or angular direction; and 
 forms the reference color map. 
 
 
     
     
       5. The hyperspectral imaging system of  claim 1 , wherein:
 the reference circle map has a circular shape, which forms a circular reference color map; 
 the circular reference color map has an origin; and a radial direction and an angular direction, with respect to the origin of the circular reference color map; and 
 wherein the image forming system has a configuration that:
 varies color in the radial direction and keeps color uniform in the angular direction to form a radial reference color map; and/or varies color in the angular direction and keeps color uniform in the radial direction to form an angular reference color map; 
 decreases brightness in the radial direction to form a gradient descent color map; and/or 
 increases brightness in the radial direction to form a gradient ascent reference color map; and 
 forms the reference color map. 
 
 
     
     
       6. The hyperspectral imaging system of  claim 1 , wherein:
 the reference color map has a circular shape, which forms a circular reference color map; 
 the circular reference color map has an origin; and a radial direction and an angular direction with respect to the origin of the circular reference color map; 
 the image forming system has a configuration that:
 determines a maximum value of a phasor histogram to form a maximum phasor value; 
 assigns a center to a circle that corresponds to coordinates of the maximum phasor value to form the circular reference color map's maximum center; 
 varies color in the radial direction and keeps color uniform in the angular direction, with respect to the circular reference color map's maximum center, to form a morph maximum value mode; and/or 
 varies color in the angular direction and keeps color uniform in the radial direction, with respect to the circular reference color map's maximum center, to form a morph center-of-mass value mode; and 
 forms the reference color map. 
 
 
     
     
       7. The hyperspectral imaging system of  claim 1 , wherein the image forming system has a configuration that:
 applies a denoising filter on both the real component and the imaginary component of each complex-valued function at least once so as to produce a denoised real value and a denoised imaginary value for each pixel; 
 wherein the denoising filter is applied:
 after the hyperspectral imaging system transforms the formed intensity spectrum of each pixel using the Fourier transform into the complex-valued function; and 
 before the hyperspectral imaging system forms one point on the phasor plane for each pixel; and 
 
 uses the denoised real value and the denoised imaginary value for each pixel as the real value and the imaginary value for each pixel to form one point on the phasor plane for each pixel. 
 
     
     
       8. The hyperspectral imaging system of  claim 7 , wherein the image forming system has a further configuration that estimates error after it applies the denoising filter. 
     
     
       9. The hyperspectral imaging system of  claim 7 , wherein the image forming system uses a first harmonic and/or a second harmonic of the Fourier transform to generate the unmixed color image of the target. 
     
     
       10. The hyperspectral imaging system of  claim 1 , wherein:
 each phasor point has a real value and an imaginary value; 
 the image forming system has a configuration that:
 forms a phasor plane by using a coordinate axis for the imaginary value and a coordinate axis for the real value; 
 forms a phasor bin, wherein the phasor bin comprises phasor points and has a specified area on the phasor plane, and wherein a number of the phasor points that belong to the same phasor bin forms a magnitude of the phasor bin; and 
 forms a phasor histogram by plotting the phasor bin magnitudes. 
 
 
     
     
       11. The hyperspectral imaging system of  claim 10 , wherein the hyperspectral imaging system has a configuration that forms a tensor map by calculating a gradient of the phasor bin magnitude between adjacent phasor bins; and assigning a color to each pixel based on the reference color map. 
     
     
       12. The hyperspectral imaging system of  claim 10 , wherein the hyperspectral imaging system is a system for real-time intrinsic signal image processing, a system for separation of 1 to 3 extrinsic labels from multiple intrinsic labels, a system for separation of 1 to 7 extrinsic labels from multiple intrinsic labels, and/or a system for combinatorial label visualization. 
     
     
       13. The hyperspectral imaging system of  claim 10 , wherein the image forming system uses at least a first harmonic and/or a second harmonic of the Fourier transform to generate the unmixed color image of the target. 
     
     
       14. The hyperspectral imaging system of  claim 10 , wherein the image forming system uses a first harmonic and/or a second harmonic of the Fourier transform to generate the unmixed color image of the target. 
     
     
       15. The hyperspectral imaging system of  claim 10 , wherein the target radiation comprises at least four wavelengths. 
     
     
       16. The hyperspectral imaging system of  claim 10 , wherein the target radiation has four wavelengths or eight wavelengths. 
     
     
       17. The hyperspectral imaging system of  claim 10 , wherein the hyperspectral imaging system forms the unmixed color image of the target at a signal-to-noise ratio of the at least one intensity spectrum in a range of 1.2 to 50. 
     
     
       18. The hyperspectral imaging system of  claim 10 , wherein the hyperspectral imaging system forms the unmixed color image of the target at a signal-to-noise ratio of the at least one intensity spectrum in the range of 1.2 to less than 3. 
     
     
       19. The hyperspectral imaging system of  claim 10 , wherein the image forming system has a further configuration that performs multispectral volumetric time-lapses with reduced photo-damage after it forms the at least one intensity spectrum for each pixel. 
     
     
       20. The hyperspectral imaging system of  claim 10 , wherein the image forming system has a further configuration that identifies autofluorescence as a spectral fingerprint and removes the autofluorescence.